Apparatus for screen molding three-dimensional objects

ABSTRACT

Three-dimensional objects are molded by advancing a special squeegee member along a flexible screen or the like to which a perforated mold is affixed, and pressing the mold into progressive engagement with a substrate, while at the same time, causing the squeegee to force the molding material through the screen and into the mold cavity, the mold stripping automatically and cleanly from the deposited material behind the squeegee as it is advanced.

States 'atent [1 1 Elite Baker 1 APPARATUS FOR SCREEN MOLDINGTHREE-DIMENSIONAL OBJECTS I [75] Inventor: Harold L. Baker, Kansas City,Mo.

[73] As'signee: Rayette-Faberge lnc. ,New York,

221 Filed:' Dec. 21, 1970 211 Appl. No.: 100,292

' Related US. Application Data [62] Division of Ser. No. 806,419, March12, 1969, Pat.

[ 51 Aug. 7, 1973 Primary Examiner.l. Spcncer Overholser AssistantExaminer-David S. Safran Attorney-Schmidt, Johnson, Hovey & Williams [57] ABSTRACT Three-dimensional objects are molded by advancing a specialsqueegee member along a flexible screen or the 1 C1 425/1310 311, 1 liketo which a perforated mold is affixed, and pressing 1 18/406 the moldinto progressive engagement with a substrate, [51] Int. Cl 829d 9/08whil t the same time, causing the squeegee to force 1 1 Field 01 Searchthe molding material through the screen and into the 425/ 1310- 1;118/406; l0 mold cavity, the mold stripping automatically and 129cleanly from the deposited material behind the squeegee'as it isadvanced. [56] References Cited UNITED STATES PATENTS 1 Claim, 10Drawing Figures 1,922,710 8/1935 Owens 101/123 v 7 g V 4 A 1 1 1 L 94 l8l6 PAIENIEU AUG 71975 saw 2 OF 2 STr'ip Cool Oven

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Load CocnI 1 APPARATUS FOR SCREEN MOLDING THREE-DIMENSIONAL OBJECTS Thisis a division of my copending application Ser. No. 806,419 filed Mar.12, 1969, now Patent No. 3,658,977. It is an important object of mypresent invention to provide a novel molding method and apparatus whichwill permit production in a somewhat assembly line fashion of athree-dimensional article in successive molding operations within aperiod of time that is only slightly greater than that required to pourthe molding material into the mold.

Another important object of the instant invention is the provision ofmethod and apparatus for rapid and economical production of multilayerarticles in a manner to produce various designs and configurations bychemical bonding of the layers one to another.

Still another important object of my instant invention is to producemolded articles by progressive building up of successive layers whichwill permit formation of various designs and configurations of differentcolors.

A further object of the present invention is to provide for rapid,automatic removal of the mold from the molded article in a manner toshear the edges of the molding material prior to final cure, therebycom-. pletely eliminating the need for secondary fabrication.

Another aim of the present invention is to attain intricate design anddetail on the article of manufacture to an extent previously deemedimpossible in conventional molding procedures and equipment.

In the drawings: I

FIG. 1 is 'a side elevational view of apparatus for screen molding ofthree-dimensional objects made in accordance with my present inventionand capable of use in carrying out my novel method, parts being brokenaway for clearness;

FIG. 2 is an end elevational view of the apparatus illustrated in FIG.1, parts being broken away and in section to reveal details ofconstruction;

FIG. 3 is an enlarged end view of the squeegee assembly, showing its armsupport in section, parts being broken away and in section forclearness;

FIG. 4 is a fragmentary, detailed cross-sectional view taken onirregular line 4-4 of FIG. 3 looking in the direction of the arrows;

FIG. 5 is a vertical, enlarged fragmentary crosssectional view throughthe apparatus illustrated in FIGS. 1 and 2 illustrating the action ofthe squeezee in placement of the molding material into the mold and onto the substrate;

FIG. 6 is an enlarged fragmentary cross-sectional view showing thevacuum board as in FIG. 5, the substrate, the mold, and the flexedscreen as the squeegee acts thereon and deposits the material onto thesubstrate;

FIG. 7 is an enlarged fragmentary perspective view of a portion of;themold, its flexible support and the mounting frame;

FIG. 8 is a diagrammatical representation of the man ner of use of theapparatus while producing the article in large numbers successively;

FIG. 9 is a plan view of the screen registry board em-. ployed whenmultilayer "articles are to be produced; and

FIG. 10 is a fragmentary detailed cross-sectional view taken on line10-10 of FIG. 9.

In FIGS.'1 and 2 of the .drawings, the molding apparatus as illustratedincludes a suitable supporting base 12, horizontally disposed and havinga flat uppermost surface 14 adapted to support a vacuum board 16,provided with a plurality of openings '18 (FIGS. 5 and 6) for purposesto hereinafter be made clear.

The top surface 14 of the base 12 also supports an open frame 20 throughthe medium of a plurality of hinges, one of which is illustrated in FIG.1 and desig nated by the numeral 22. It is noted in FIGS. 1 and 2 thefour sides of the polygonal frame 20 are made from angle iron or thelike presenting horizontal and vertical legs 24 and 26 respectively, thelegs 24 being in turn supported by blocks 28 remote from hinges 22 tomaintain the legs 24 in substantial parallelism with the surface 14 ofbase 12.

That end of the frame 20 remote from hinges 22 is held tightly againstthe blocks 28 by an elongated arm 30 extending longitudinally of theframe 20 thereabove and mounted on the base 12 through the medium of astandard 32 secured to base 12 and extending upwardly from the latteradjacent the hinges 22. The transversely circular arm 30 is swingablyattached at. one end thereof to the standard 32 by a pivot pin 34 andthe opposite end of the arm 30 bearsagainst an upwardly extending bar 36rigidly secured to leg.26 at that end of the frame 20 opposite to hinges22 The arm 30 ,is releasably heldin the-position shown in FIGS. 1 and 2,holding the frame 20 against the blocks 28 by ahorizontally slidable,latch 38 carried by a post 40 that is in turn secured to and extends upwardly from the face 14 of base'l2.

A second, open, polygonal frame 42 (see' also FIG. 7) is removablydisposed within the confines of frame 20 resting on legs 24 and held inplace by a plurality of releasable clamps '44 swingably mounted on theouter faces of the legs 26 of frame 20. Each clamp 44 is provided with abolt and wing nut arrangement 46 adapted to maintain lateral extensions48 in tight engagement with the frame 42 thereabove.

The frame 42 has a flexible member 50 secured to the normally lowermostface of frame 42 within grooves 52 in full covering ,relationshipto theinnermost polygonal opening 54 that is defined by the continuous frame42.

The member 50 has a stencil mold 56 bonded or otherwise affixed to itsnormally lowermost face, mold 56 being in turn provided with aperforation 58 of any desired configuration, depending upon the shapeand size of the molded article to be produced by the apparatus andmethod of my invention.

The member 50 may, if desired, be imperforate throughout except at theperforation 58, at which zone tion the member 50 should be maintainedrelatively.

taut across the opening 54 in the frame 42.

A squeegee assembly broadly designated by the numeral 62 (also shown inF I68. 3 and 4) is supported by the arm 30' for reciprocation therealongabove the member 50 and within the confines of the opening 54 in frame42. Assembly 62 includes an elongated block 64 having a length at leastas wide as the mold 56 or, if desired, somewhat shorter than the widthof the mold 56 provided that block 64 is as long as the maximum width ofthe perforation 58. As seen in FIGS. 2 and 3, the block 64 is providedwith a sleeve 66 thereacross which receives the arm 30.

Block 64 has a squeegee element 68 suspended therefrom through themedium of a plurality of bolts 70 extending loosely through the block 64and provided with nuts 72 for adjustment of the extent of movement ofthe squeegee 68 downwardly away from the block 64.

The squeegee 68 is essentially in the nature of an elongated rigidcylinder except only for the provision of a longitudinally extending,transversely arcuate rib 74 on the lowermost surface of the squeegee 68.It is to be preferred that squeegee 68 be coated with a suitableresilient material such as rubber.

Squeegee 68 has an elongated longitudinally extending guide bar 76affixed to its uppermost surface and shiftable vertically within theconfines of a downwardly facing cavity 78 formed in the block 64. Heads80 of bolts 70' are permanently embedded within the bar 76 as shown inFIG. 3.

Cavity 78 also receives an elongated plate 82 which loosely receives thebolts 70. A plurality of coil springs 84 are interposed between the bar78 and the plate 82, and a number of adjustable L-shaped stops 86carried by the block 64 limit the extent of upward movement of the plate82 within cavity 78.

The board 16 as best seen in FIGS. and 6 supports a substrate 88 whichis preferably in the nature of a flat rigid plate having smooth paralleluppermost and lowermost surfaces. The board 16 may be used to positivelyhold the substrate 88 in place by drawing a vacuum on the substrate 88through the openings 18. It is to be understood, however, that thesubstrate 88 may be held on the board 16 in any other suitable mannersuch as by use of clamps (not shown). Moreover, the board 16 may beentirely eliminated and the substrate 88 firmly attached to the surface14 of base 12.

Assuming all of the component parts thus far described to have beenassembled, clamped and otherwise held in place, as illustrated in FIGS.1 and 2 of the drawings, the apparatus is now ready for use in themolding of three-dimensional objects. With the assembly 62 disposed ateither end of its reciprocable path of travel, it is seen in FIGS. 1 and2 that the squeegee element 68, and particularly the rib 74 if used,will directly engage the upper surface of the member 50, flexing itdownwardly toward the substrate 88 both longitudinally as shown in FIG.1 and transversely as shown in FIG. 2. Prior to commencement of themovement of the assembly 62 toward the opposite end of its path oftravel along the arm 30, a supply of molding material 90 is fed in anysuitable manner onto the upper surface of the member 50 ahead of thesqueegee 68 and directly within its path of travel. As the squeegee 68approaches the proximal end of the mold 56 it will cause the flexiblemold 56 to move into firm engagement with the substrate 88,progressively closing the perforation 58 therebeneath and presenting acavity in the mold 56 for'reception of the material 90.

Simultaneously with such progressive downward flexure of the member'50and the mold 56 squeegee 68 will force the material 90 through themember 50 at the perforation 58, depositing the material 90 onto theupper flat smooth surface of substrate ,88 within the confines of theperforation 58.

The feeding of the material 90 to the member 50 ahead of the squeegee 68should of course be controlled within certain limits, making sure thatthere is always a sufficient supply of the material 90 to completelyfill the cavity within mold 56 that is defined by the perforation 58.However, excess material will freely flow laterally in both directionsbeyond the ends of the squeegee 68 as is evidentfrom FIG. 2. For themost part, however,,the material 90 will build up ahead of the squeegee68 as illustrated in FIG. 6 and such material 90 as becomes excessivewill flow ahead of the squeegee 68 as it is advanced.

It is extremely important that the squeegee 68 be relatively rigid asaforementioned in order to provide a smooth surface 92 for the depositedmaterial 94 constituting the article of manufacture molded by theillustrated apparatus'and in accordance with the method of my invention.Moreover, it is to be desired that the surface 92 be substantiallyparallel with the lower surface of the article 94 that engages thesubstrate 88 and such is assured by the nature of the squeegee 68 asabove described. I

It is to be understood that the member 50, particularly when the sametakes the formof a screen mesh, has a somewhat irregular upper surface;therefore, such is accommodated by the relatively thin resilient coatingon the squeegee 68.

The rib 74 is advantageous from the standpoint of providing a line ofconcentrated pressure of the squeegee 68 on the member 50 and on themold 56, thereby assuring positive feed or pressure of the material intothe cavity defined by perforation 58 such that the cavity will becompletely filled with the material 90 while at the same timemaintaining the flat, relatively smooth surface 92 in parallellism withthe substrate 88.

As the squeegee 68 advances along the mold 56 to progressively bring itinto engagement with the upper surface of substrate 88 and as thematerial 90 is forced into the cavity of mold 56 as above described, themold 56 is, at the same time, progressively stripped from the depositedmaterial 94 as illustrated in FIG. 6, leaving material 94 deposited uponthe substrate 88 and this is extremely advantageous in that it leavesthe finished article with smooth sharp edges throughout the peripheralboundaries thereof conforming exactly to the configuration of theperforation 58 and also conforming precisely with the thickness of themold 56, it being understood that the thickness of the finished article94 is predetermined by a preselection of the thickness of the mold 56.

After completion of the cycle the article 94 is removed and heat curedin any suitable manner. On the return stroke of the assembly 62 the nextsuccessive article 94 is molded in the same manner.

It is to be noted, particularly in FIGS. 3 and 4, that the springs 84impart'a yieldable bias on the squeegee 68 so as to maintain a fullengagement of the mold 56 with the substrate 58' as the squeegee isadvanced. Moreover, by adjustment of the stops 86 within the block 64 itis possible to control the amount of material 90 that is pressed intothe cavity of mold 56, thereby assuring the operator that such cavity isalways completely filled without any'excessive buildup of the material90 above the mold 56 and therefore above the flexible member 50. Stillfurther, in the event that molds 56 are employed which do not haveplanar, parallel top and bottom surfaces (as for example when thefinished product is to have areas of differing thickness), the springs84 will accommodate the necessary, slight vertical movement of thesqueegee 68 as it is advanced.

Another important feature and adaptation of the apparatus and methodjust above described is its use in the production of finished articleshaving various designs embossed into' or raised upon the surface 92 ofthe article 94.

After the first pass of the squeegee 68 utilizing the mold 56, the frame42 is entirely removed from within the frame 20 by releasing latch 38and the frame 42 is replaced with another frame 42 having a mold 56provided with a perforation S8 of a differing configuration.

Additionally, adustment is made to raise the squeegee 68 through use ofbolts 70 and nuts 72 with the stops 86 backed off accordingly. Thereuponon the next pass of the squeegee 68 across the new mold 56 a top layerof material90 is placed upon the previously deposited material 94,presenting a raised design or configuration thereon, it being understoodthat the material shall be of such nature asto bond together into acomposite unit during subsequent curing.

Still further, unique appearances and useful articles can best beproduced by utilizing differing colors in the two or more layers ofmaterial that are molded into place during successive operations as justexplained.

Alternately, in lieu of removal of the frames 42 and replacement withsuccessive frames 42 it might be still more advantageous to provide aseries of molding assemblies each having a frame 42 with a mold 56 of acharacteristic shape in its perforation 58. In such event after formingthe first layer in the first of such assemblies as illustrated in FIG. 6such first layer and/or the substrate 88 with the layer thereon would beremoved and transferred to the second molding unit for the purpose ofdepositing the second layer. Such steps could be continued until thedesired number of layers of material are provided'in the finishedarticle.

Still another adaptation is to provide a pocket of a desired shape andsize in the finished article. This could be done by placing a blockingagent on the first layer at a desired location thereon prior toplacement of the next successive layer, such blocking agent serving toprevent formation of the material within the zone of such agent.

The blocking agent, as for example polyvinyl alcohol, may be placed onthe first layer through use of a mold 56 in the same manner as abovedescribed. When the third layer is molded into place, the blocking agentwill prevent bonding at the zone of the blocking agent, presenting theaforementioned pocket, the latter of which may have an'access 'orentrance mouth. at one edge of the finished article, all as preselectedthrough choice of the proper mold 56 used during placement of theblocking agent.

Another manner of providing an opening through the finished article isto utilize at the outset for the material 90 a preselected vinylplastisol but prior to placement of such material 90 onto-the substrate88 a preselected area on substrate 88 is provided with a contaminantcapable of blocking the flow of the vinyl plastisol tothe areacontaining the contaminant. Such contaminant may be in the form ofliquid silicone operating to prevent wet out of the vinyl plastisolonthe substrate88 in the area or areas where the contaminant is initiallyplaced on the substrate 88.

It is to be understood at this juncture that in carrying out the methodof my invention, a wide variety of materials may be employed. Forexample, it is contemplated that in certain instances a moldable liquidwill be used and the rheology thereof will be carefully controlled suchas by use of silica gel therein.

The rheology of the moldable liquid may also be controlled withsynthetic cells such as glass microballoons. It is to be understoodfurther that the completed article may have a cellular structureimparted thereto by use of a blowing agent in the material 90, such asair or a gaseous substance, e.g., nitrogen.

In the event a latex is employed for the material 90, as might bedesired in the production of certain threedimensional articles, it isnecessary to give the latex an ionic charge through use of a suitablesolvent. More over, the substrate 88 should also be coated with asubstance having an ionic charge, such charge being opposite to that ofthe latex material. When these procedures are followed, the latex iscaused to coagulate during placement on the substrate 88, giving thismaterial 90 adequate body to form'the desired finished product.

When ceramic clay .is used for the material 90, it is necessary toutilize a plaster substrate capable of absorbing the moisture content oftheclay material 90.

In all events, if it is desired to provide a somewhat rough and/orirregular surface 92 in the finished article 94, such surface may beprovided with a layer of a thermoplastic powder which will bond to thematerial 90 during curing.

It is to be understood still further that through use of the method andapparatus herein described, it is possible to cause the substrate 88 tobecome a part of the finished article. In that event, by selection ofthe desired material in substrate 88 the material 90 can be bondedpermanently to the substrate 88.

In FIG. 8 of the drawings there is diagrammatically illustrated a mannerof adaptation of the apparatus and method into what might be called anassembly line production. Through use of a continuous conveyor belt 96successive substrates 88 are placed upon the upper stretch of theconveyor 96 at load" zone 98 for movement in the direction of arrow 100.When the substrate 88 reaches the coat" zone 102, a layer 94 of material90 is deposited upon the substrate 88 through use of one of theassemblies shown in FIGS. 1 and 2.

The substrate 88 with its deposited layer thereon then advances to aheat zone 104 for curing purposes and thence to a cool zone 106.

The zones l04,and 106 are exemplary only and utilized only when thenature of the material 90 is such as to require curing through use ofheat followed. by the desired cooling step. t I

In any event the steps 104 and 106 would normally be employed where itis necessary to gel or partially solidify or cure the first layer 94.

The substrate 88 with the solidified layer 94 thereon then passes to asecond coat" zone 108 for placement of a second layer in the mannerabove described. Here again, the second layer may pass through heat zone110 and cool zone 112 before advancing to a third coat zone 114 for thepurpose of placement of a third layer. At this juncture, assuming that adesired number of layers are molded in place, the article manufacturedadvances to an oven 1 16 for final curing. After cooling in zone 118,the finished article is stripped from the substrate 88 at zone 120.

It is contemplated that FIG. 8 illustrates a continuous process whereinsuccessive substrates 88 are placed on the conveyor 96 in timed sequenceso that the finished articles will emanate from the conveyor 96 on alarge scale production basis.

It is necessary when molding articles of successive layers of material90 that the multitude of differing molds 56 be relatively oriented sothat the designs or configurations are properly located in accordancewith the desires of the manufacturer. For example, the second layer maytake the form of lettering, a representation of a building, scenery, theoutline of an animal or the like, ad infinitum. In some instances suchconfigurations will be centered on the face 92; in other instances theywill be offset, as for example adjacent one edge or corner of theinitial layer 94.

Such proper orientation of the successive molds 56 may be accomplishedthrough use of the device illustrated in FIGS. 9 and 10 of the drawings.A panel 122 is provided with an L-shaped locating flange 124 forreceiving frame 42 resting on the upper face of panel 122. Releasableclamps 126 on the panel 122 are employed to properly hold the frame 42in place.

The panel 122 is provided with a pair of diagonal slots 128 each ofwhich is in turn provided with shiftable registration blocks 130 thatare releasably held in place by bolt and nut means 132.

In registering a series of frames 42 each having flexible members 50joined thereto with stencil molds 56 affixed to the members 50, theoriginal art work (not shown) from which the stencil molds 56 are to becut is placed on panel 122 and blocks 130 are moved in slots 128 untilthey are in alignment with four spaced points on the original art work.A suitable marking material such as artists type is placed on theexposed surface of blocks 130 in order that the location of the blocks130 may be recorded as registration marks" on the original art work. Thefirst stencil mold 56 is formed using conventional techniques, e.g., aphotographic emulsion, to give a perforation 58 duplicating a portion ofthe original art work.

The location of blocks 130, recorded as "registration marks" on theoriginal art work, is transferred to the first stencil mold 56. The mold56 is then placed on panel 122 carefully aligning the marks on the mold56 with the blocks 130. Frame 42 is mounted on panel 122 using clamps126 as illustrated in FIG. 9. It is to be understood that the insidedimensions of flange 124 must conform to the outside dimensions of frame42 in order to insure proper registration of a series of molds 56.Flexible member 50 (omitted in FIG. 9 for purposes of illustration)affixed to frame 42 is joined to the previously registered stencil mold56 using a suitable adhesive. The above procedure, commencing with thetransfer of the registration marks to the stencil mold 56 is thenrepeated for each stencil mold 56 which is to have a perforation 58forming a part of the original art work. This procedure will insure thatall of the stencil molds 56 forming a part of a single piece of originalart will be in proper alignment when placed in the apparatus illustratedin FIGS. 1 and 2.

Having thus described the invention, what is claimed as new and desiredto be secured by Letters Patent is:

1. Screen molding apparatus comprising: a frame; a flexible memberattached to the frame; a perforated mold joined to the member, saidmember having a portion at the perforation of the mold adapted for flowof molding material through the member and into the perforation; andmeans for flexing the member toward a substrate to move the mold intoengagement with the substrate across the perforation and forsimultaneously forcing said material through the member, into theperforation and onto said substrate, whereby to form a three-dimensionalobject conforming to the configuration of the perforation andsubstantially to the thickness of the mold, said means comprising anelongated, cylindrical element, longitudinally rigid, with the outersurface thereof formed of a resilient material, said element beingprovided with a member-engaging rib extending the length of saidelement.

1. Screen molding apparatus comprising: a frame; a flexible member attached to the frame; a perforated mold joined to the member, said member having a portion at the perforation of the mold adapted for flow of molding material through the member and into the perforation; and means for flexing the member toward a substrate to move the mold into engagement with the substrate across the perforation and for simultaneously forcing said material through the member, into the perforation and onto said substrate, whereby to form a three-dimensional object conforming to the configuration of the perforation and substantially to the thickness of the mold, said means comprising an elongated, cylindrical element, longitudinally rigid, with the outer surface thereof formed of a resilient material, said element being provided with a member-engaging rib extending the length of said element. 